This invention relates to muffler plugs for a gas turbine engine and particularly to means for compartmentizing the plug for sound absorption effectiveness while having good structural integrity notwithstanding the hostile environment.
A problem that existed heretofore is that the adversity accompanying the thermal growth because of the hostile environment made compartmenting difficult, if not impossible, compartmenting has advantages for sound suppression effectiveness but because of the stress problems encountered the development of this acoustic technique has been curtailed.
I have found that I can obviate the above referenced stress problems by forming the walls of the compartments with axially facing spaced cones that are interference fitted so that the cone base bears against the inner diameter of the plug wall. Pressurization of the compartments forces the cones into their seats and enhances the radial readjustment during thermal growth. Additionally, the plug tubes admitting grazing flow and pressure waves into the compartments are oriented to face the slanted wall of the cones to further enhance sound absorption.